1. Field of the Invention
The present general inventive concept relates to a toner and a process of preparing the same, and more particularly, the present general inventive concept relates to a toner used in an electrophotographic process and a process of preparing the same.
2. Description of the Related Art
In an electrophotographic process or an electrostatic recording process, a developer which is used to form an electrostatic image or an electrostatic latent image may be a two-component developer, which is formed of a toner and carrier particles, or a one-component developer, which is formed of only a toner. The one-component developer may be a magnetic one-component developer or a nonmagnetic one-component developer. Plasticizers such as colloidal silica are independently added to the nonmagnetic one-component developer in order to increase a flowability of the toner. In addition, coloring particles obtained by dispersing a colorant, such as a carbon black, or other additives in a binding resin, are also used in the toner.
Methods of preparing toners include pulverization and polymerization. In the polymerization process, a polymerizable monomer composition is manufactured by uniformly dissolving or dispersing a polymerizable monomer, a colorant, a polymerization initiator and, if needed, various other additives, such as a cross-linking agent and an antistatic agent. Next, the polymerizable monomer composition is dispersed in an aqueous dispersive medium, which includes a dispersion stabilizer, using an agitator to form minute liquid droplet particles.
Subsequently, a temperature is increased and suspension polymerization is performed to obtain a polymerized toner having colored polymer particles of a desired size. In particular, there has been proposed a method for preparing a toner with a structure of a core and a shell which can be prepared by forming the core using a vinyl monomer and an initiator, and then forming the shell by polymerizing a vinyl monomer having particles whose hydrophilicity is larger than or equal to that of the particles of the core and having a larger glass transition temperature (Tg) than that of the core. However, this proposed method has limitations in that the shell needs to be thick in order to create a core-shell structure and also to improve a storability.
In the pulverization method, the toner is obtained by melting and mixing synthetic resins with colorants and, if needed, other additives, pulverizing the mixture, and then classifying the particles until particles of a desired size are obtained. However, in view of the features of the toner prepared by pulverization and drying, when the content of the wax is greater than 2.5% by weight, a durability and a storage stability of the toner is impaired. Accordingly, it is not desirable to increase the content of the wax for the purpose of preventing an offset phenomenon or improving the fixing ability of the toner. In addition, the toner prepared by pulverization unavoidably includes portions of wax protruding outwardly, the waxes serve as external additives during a pulverizing process, but cause part of the toner to be blocked, thereby resulting in a poor image quality and a deteriorated storage stability of the toner.
Due to a recent demand for high speed image forming devices, in an electrophotographic imaging apparatus using electrophotography or electrostatic recording, such as a photocopier, a laser printer, or an electrostatic recorder, toners for developing an electrostatic image which use a low-temperature fixing developer would be desirable.